The purpose of this study is to provide an intervention that will help shorten the duration of the painful crisis. Fructose-1,6-diphosphate (FDP) is a phosphorylated sugar that is present naturally in the human body. Its anaerobic metabolism proceeds by way of glycolysis and yields 4 mol ATP per mol of FDP which is twice the yield of glucose. If FDP can help the red cell resist the stimulus to form the sickle shape, by increasing the intracellular availability of ATP, then administration of FDP early in a crisis could shorten its duration. Four to eight subjects will be entered in stage two/three. In stage two/three subjects are given one infusion over thirty minutes q 6 hours over 72 hours. Stage three is an open label infusion q 6 hours for an additional 1-7 days. The duration of Stage 3 will vary from patient to patient. To date, we have enrolled 7 patients. We were recently notified that the sponsoring company has closed enrollment after reaching their desired number of study subjects from among the various centers, therefore we will not be enrolling any more patients on this protocol.